Apparatus for producing folded strip material

ABSTRACT

Apparatus for forming zig-zag folded strip in which the strip is folded about anvil plates by means of alternately acting folding dies. Two anvil plates are provided and are moved into and out of position in synchronism with successive folding operations of the folding dies. The movement of the anvil plates is effected in a direction transverse to the plane of the strip.

United States Patent Trihey Jan. 29, 1974 [54] 2;; $3 122 533 RODUCING FOLDED FOREIGN PATENTS OR APPLICATIONS 469,322 12/1928 Germany I. 72/403 [75] Inventor: John Massey Trihey, Balwyn,

Victoria, Australia P E L n L 0 rimary xaminerowe A. arson [73] AssIgnee: Vulcan AustrahaLImlted, Burwood, Attorney Agent or pirm cushman, Darby &

Vlctoria, Australia Cushman [22] Filed: Sept. 14, 1971 [21] Appl. No.: 180,438

[57] ABSTRACT [30] Foreign Application Priority Data A f f f Id d h h 14 l' pparatus or ormmg zxg-zag o e Stnp m W Sept I970 Austvra 251 I the strip is folded about anvil plates by means of alter- [52] Us. CL 72/381 72/403 nately acting folding dies. Two anvil plates are pro- [51] Int. Cl B21d 13/02 vided and are moved into and out of position in syn- [58] Field 4 385 403 chronism with successive folding operations of the folding dies. The movement of the anvil plates is effected in a direction transverse to the plane of the [56] References Cited UNITED STATES PATENTS 13 Claims, 11 Drawing Figures 2,489,125 ll/l949 Dyson 72/403 [J r/2 /5 3 M I 1 2 o o/ -1\ HQ 7 T 5/-- 24 53 r 52 APPARATUS FOR PRODUCING FOLDED STRIP MATERIAL This invention relates to an apparatus for the formation of metal strip material into an alternatelyfolded zig-zag configuration and is designed chiefly to provide a simple and effective means for the formation of strip elements for use in the heat exchanger elements for our copending U.S. Pat. application No. 2,511/70 now US. Pat. No. 3,659,518 from which this application is divided. The apparatus may, however, be useful for the formation of folded strip for other purposes and it is to be understood that such other uses are not disclaimed.

The folding of strip to a zig-zag configuration may be accomplished by crimping the strip between meshing teeth and then longitudinally compressing the crimped strip. This has, however, the drawback that the folds are rounded or pointed and poor contact is obtained between the strip and heat exchange surfaces with which they are engaged. Furthermore, such strip is usually formed with louvres punched in each panel of the folded strip and since this must be done before the strip is folded it is necessary to provide a folding method which does not damage the louvres. The principal object of this invention is therefore to provide an apparatus for folding strip in the manner indicated, in which the folds are positively formed about a former at each folding operation.

According to this invention there is provided an ap-' paratus useful for the zig-zag folding of metal strip comprising a frame carrying a folding mechanism, said folding mechanism having folding means to cause folding of the strip alternatively first in one direction and then the other, an anvil plate adapted to move to a first position to intersect the path of the strip and to lie transversely of the strip as the folding means folds the strip about the anvil and thereafter to move to a second position clear of the folded strip to allow the thus folded strip to be advanced past the folding mechanism, and means to causethe anvil plate to move successively between said first position and said second position in a cyclic operation in synchronism with the operation of the folding means. Preferably the anvil plate is arranged to move from its first position to its second position in the transverse direction of the plane of the strip. Preferably also there is provided means to move the anvil plate in the direction of advance of the strip.

There are preferably two anvil plates arranged in parallel planes and adapted to move in opposite directions whereby' as one plate ismoved from its first position to its second the other plate moves from its secondposition to its first. Preferably, also the plates are operated sothat as one plate, in its first position is moving in the direction of advance of the strip, the other plate, in its second position, is moving in a direction opposite to said direction of advance. Thus, during any cycle of operation the locus of any point on the surface of an anvil plate will be a quadrilateral.

The anvil plates are preferably each mounted on carriage members which are floatingly carried and slidable with respect to the machine frame. Preferably also each carriage carries an additional support plate member arranged to lie in a plane parallel to the anvil plate and spaced from it a distance equal to one fold of the strip said support plates acting to support the folded strip as one anvil plate is moved to its second position and the other is moved to its first position.

The folding means preferably comprises a pair of pivotted folding dies arranged one on each side of the strip and arranged to operate successively to fold the strip first in one direction about one anvil and then in the other direction about the other anvil.

The invention will now be more fully described with reference to the accompanying drawings in which there is illustrated one form of apparatus which may be constructed according to the invention. In the drawings:

FIG. 1 is a plan view of the apparatus;

' FIG. 2 is a cross-sectional view on an enlarged scale on the line 2-2 in FIG. 1;

FIG. 3 is a cross-sectional view on the same scale as FIG. 2 on the line 3-3 in FIG. 1 showing the carriage members moving in one direction;

FIG. 4 is a view similar to FIG. 3 showing the carriage members moving in the opposite direction;

FIG. 5 is a view on a still further enlarged scale of portion of the folding mechanism shown in FIG. 2 showing the commencement of a folding operation;

FIG. 6 is a view similar to FIG. 5 showing the completion of the folding operation;

FIG. 7 is a cross-sectional view on the line 77 in FIG. 6 and showing one carriage member with its anvil plate in its first position;

FIG. 8 is a view similar to FIG. 7 showing the said one carriage moving towards its second position and the other carriage moving into its first position;

FIG. 9 is a view similar to FIG. 8 showing the other carriage member moved into its first position;

FIG. 10 is a view similar to FIG. 5 showing the commencement of the next folding operation; and

FIG. 11 is a view similar to FIG. 5 showing a modification of the apparatus.

The apparatus illustrated in the drawings is designed particularly for the production of folded strip for heat exchange elements of the type described in our copending US. Pat. application No. 2,51 1/70. The apparatus comprises essentially a table frame 1 on which there is mounted a folding mechanism 2 and a stamping mechanism 3. The folding and stamping mechanisms are driven in synchronism from a suitable power source (not shown) by means of suitable chaindrives 4, gear- 7 box 5 and connecting links which will be'more fully described hereinafter.

The apparatus is designed automatically to receive strip material 6 of aluminium or the like, and to punch louvred sections 7 which are separated from adjacent louvred sections by plane sections 8 and to feed the strip so formed to the folding mechanism for folding of the louvred strip into a zig-zag configuration. The stamping mechanism comprises a simple platen 9 and a reciprocated stamping die 11 carried by bearings 12 on stub shafts 13. The stamping die is reciprocated by means of an eccentrically mounted crank mechanism 14 which is driven in synchronism with a folding mechanism by means of chain drive 4 from sprocket 15 which is in turn mounted on the same shaft as connecting rod 16 which operates the folding mechanism. As shown in FIG. 2 the stamping mechanism is mounted on a common frame 17 with the folding mechanism and is immediately above it.

The folding mechanism comprises first of all a pair of folding dies 21,22, which are pivotally mounted on brackets 23 secured to the frame member 17. They are connected together by means of a connecting link 24 and are connected in turn to the reciprocable connecting rod 16.

Mounted transversely of the stamping and folding mechanism frame 17 is a further frame 30 which will hereinafter be called the anvil frame comprising a pair of spaced beam elements 31, 32 which support carriage members 33, 34 which in turn carry anvil plates 36, 37 and support plates 38,39.

To understand the construction of the carriage members it is necessary to consider FIGS. 3 to 7 in conjunction. It will be seen from FIGS. 2, and 6 that the carriage members are generally I-I-shaped in cross section with the web of the section bifurcated at one end (see FIG. 7). Into the bifurcated section 41 of the carriage 33 there projects the anvil plate 36 which is secured to one side of the carriage member and the support plate 38 which is secured to the other side. The flanges of the carriage members each carrying upper and lower cam sections 44, 45, 46 and 47. The carriages are mounted between the frame members 31, 32 by means of friction pads 48, 49 so that they are generally held in position relative to the frame. The carriage members are also located relative to the frame by means of traction elements 51, 52 which are in turn connected to a connecting link 53 mounted on rollers 54,55 in slideways 56, 57. The connecting link is connected at one end to a connecting rod 58 which is in turn connected to an eccentric element 59! mounted on shaft which also carries the drive to the stamping and folding mechanism previously described.

For further clarification, the operation of the carriage members will now be separately described with reference to FIGS. 3 and 4. FIG. 3 shows the carriage members in their positionss which they assume when they are moving to the right in that figure. The carriage member 33 is being drawn along by the traction link 52 which exerts a downward movement and therefore has the effect of drawing the carriage member downwardly onto lower rollers 61,62 and at the same time the carriage member 34 is being pushed along by the traction link 51 which exerts an upward component and therefore pushes the carriage member 34 upwardly into engagement with its upper rollers 63,64. As the movement of the assembly continues to the right the cam surfaces 46,47 on the lower side of the carriage member 33 will engage the rollers 61,62 and further movement will cause the carriage member to be lifted upwardly so that the carriage member will bear against the upper rollers 65,66. At the same time the cam surfaces 44a and 45a on the carriage member 34 will have engaged their upper rollers 63, 64 and thereby force that carriage member downwardly into engagement with its lower rollers 67,68. Thus at the end of the stroke in which the carriages are moving to the right they will have assumed the position in FIG. 4 so far as their vertical positioning is concerned. On the return stroke, i.e., when the carriages are moving to the left the reverse will occur. The carn surfaces 44 and 45 will engage the rollers' 65,66 and force the carriage 33 downwardly and the cam surfaces 46a,47a will engage the rollers 67 and 68 to force the carriage 34 upwardly. Similarly, on this stroke the traction link 51 will be exerting a downward component and the traction link 52 will be exerting an upward one.

The folding operation will now be described with reference to FIGS. 5, 6 and 7. As will be seen from those figures the anvil plate 36 and supporting plate 38 are shaped in cross-section to provide a recess 71 to accommodate one side ofa louvre element 7 and the folding die 21 is similarly recessed at 72 to accommodate the other side. The outer edge 73 of the anvil is formed to a squared configuration and the folding die 21 has a complementary square-shouldered section 74. With the apparatus in the condition shown in FIGS. 5, 6 and 7, a folding operation is commenced by the folding die 21 pivotting in a clockwise direction until the leading edge of the die engages an intermediate section 8 of the strip. Further pivotting of the folding die pushes the strip also in a clockwise direction and bends it about the upper corner of the squared section 73 of the anvil. Further pivotting of the die causes complete folding of the strip about the anvil plate and the squared section 74 of the die forces the folded strip into neat engagement with the squared end 73 of the anvil thus forming a neat squared end to the fold. Similarly at the leading edge of the die the squared end 75 forms a neat 90 fold by cooperation with the face of the anvil plate and a squared supporting shoulder 77 attached to the plate. A deflector plate 78 attached to the folding die also serves to maintain the extension of the strip in a relationship which is square to the folded portion.

The operation of the next folding step is substantially similar to that described above, but it is necessary first of all to explain the transfer operation which takes place to transfer the folded strip from the anvil and support plates carried by the carriage 33 to those carried by the carriage 34 preparatory to the next folding step. Referring now to FIGS. 7, 8 and 9, FIG. 7 as aforementioned shows the carriages and anvil plates in position which they occupy for the folding operation just described. That is, the carriage 33 and its associated anvil plates is in its first position and the carriage 34 and its associated anvil and support plates is in its second position. At the completion of the folding operation the folding dies now commence to pivot in an anticlockwise direction thus moving the die 21 out of the operative position and causing the die 22 to commence to move into the operation position. Simultaneously and in synchronism the carriages 33 and 34 commence to move to the right. It will also be observed that the carriage 33 is in its lower position and the carriage 34 is in its upper position and that in this orientation the support plate 39 of the carriage 34 is horizontally aligned with the anvil plate 36 of the carriage 33. The carriages continue their movement to the right until the condition shown in FIG. 8 is reached in which the carriage 33 is clear of the strip and the carriage 34 has moved to a position such that its support plate 39 has entered the last-formed complete fold and the anvil plate 37 is in a position immediately above the last complete fold. It will be observed that the anvil and support plates have their leading plates chamfered at 80 and 81 to assist leading in of the plates. Movement of the carriages to the right continues and as previously described with reference to FIGS. 3 and 4 the engagement between the cam surfaces and their associated rollers now causes the carriage 33 to be moved upwards and the carriage 34 to be moved downwards, thus feeding the folded strip down and placing the whole assembly in condition for the next folding operation. The folding die 22 has meantime continued its pivotal movement in an anticlockwise direction and is now in position to engage the strip with its leading edge 75a. Further movement of the die now pulls down more strip and causes folding of the strip in an anticlockwise direction about the anvil plate 37 and the formation of a square edge fold by the die surfaces 74a and 75a proceeds in the same manner as was described in respect of the formation of the previous fold.

Simultaneously and in synchronism with the aforementioned folding and transfer operations the stamping mechanism has been operating to stamp the louvres from the plane strip being fed into the upper part of the apparatus. The whole cycle operation may therefore be described as follows:

Plane strip 6 is led to the stamping mechanism and each stroke of the stamping die 11 forms louvres in the strip. One of the folding dies will then engage the strip and draw more strip past the stamping head and at the same time form a fold in the louvred strip. The transfer process above described will then operate to complete the feeding of a further section of strip into position opposite the stamping die and a further stamping operation will be carried out. A further folding and feeding operation will then be performed by the other folding die. The transfer operation will occur again and so on, so that in a continuous operation the strip is simultaneously stamped and folded.

The output from the apparatus can be led to any suitable receptacle and accumulated in any desired length. However, where the apparatus is used for the formation of heat exchange elements it will usually be desirable to produce the folded strip in standard lengths and accordingly it is convenient to provide a means for auto matically cutting the folded strip to such desired length. This may simply be achieved as shown in FIG. 11 by providing a further supporting plate'85 at the underside of a carriage member and providing a shearing knife 86 which can be set to operate automatically after the given number of folding operations in order to shear off the strip in any desired length.

l claim:

1. Apparatus useful for the zigzag folding of metal strip comprising:

a frame carrying a folding mechanism at a folding station comprising first and second folding members:

a first anvil plate and a second anvil plate each movable into and out of the folding station;

means associated with each said anvil plate to move it, in a direction transverse to the plane of the strip, to a location adjacent to and extending transversely across the strip at the folding station, and to move the anvil in the direction of advance of the strip to feed the strip through the folding station;

and synchronizing means to operate the first and second folding members in snychronism with the means for moving the anvil plates, said synchronizing means being operable to cause a cycle of operation in which:

a. the first anvil station is moved in said transverse direction, into the folding station and the second anvil plate is moved in said transverse direction away from the strip to a position clear of the strip,

b. the first folding member is operated to fold the strip about the first anvil plate,

c. the first anvil plate is moved in said direction of advance of the strip and the second anvil plate is moved in the direction opposite to said advance direction, and

d. the second anvil plate is moved in said transverse direction into the folding station and the first anvil plate is moved in said transverse direction away from the strip to a position clear of the strip.

2. Apparatus as claimed in claim 1 wherein the first and second anvil plates are mounted upon first and second carriage members, and wherein the means to move the first anvil plate and the means to move the second anvil plate include guide means, said guide means being operable to move the first carriage member in the direction of advance of the strip while moving the second carriage member in the opposite direction.

3. Apparatus as claimed in claim 2 wherein the first and second anvil plates are spaced and parallel and have adjacent ends, said guide means being operable to maintain said adjacent ends at a constant separation in said transverse direction.

4. Apparatus as claimed in claim 3 wherein said separation is less than the transverse width of the strip.

5. Apparatus as claimed in claim 3 wherein the guide means is operable to move the first and second anvil plates simultaneously in the transverse direction in the same sense, one of the anvil plates being moved transversely away from the strip so that the edge of said one anvil plate is clear of the side of the strip, the other of the anvil plates being moved transversely towards the strip at the folding station.

6. Apparatus as claimed in claim 3 wherein the guide means is operable to move the first and second anvil plates simultaneously in the transverse direction in the same sense, one of the anvil plates being moved transversely away from the strip so that the edge of said one anvil plate is clear of the side of the strip, the other of the anvil plates being moved transversely towards the strip at the folding station, wherein the first and second carriage members have first and second link members respectively pivotally mounted'thereto, the apparatus including a reciprocating bar upon which the first and second link members are mounted in mutually spaced relation, the angular orientation of one of the link members relative to the reciprocating bar being in one sense and the angular orientation of the other link member being in the opposite sense to said one sense whereby movement in one direction of the reciprocating bar will cause one of the anvil plates to move transversely away from the strip and the other of the anvil plates to move transversely towards the strip at the folding station.

7. Apparatus as claimed in claim 3 wherein the guide means is operable to move the first and second anvil plates simultaneously in the transverse direction of the same sense, one of the anvil plates being moved transversely away from the strip so that the edge of said one anvil plate is clear of the side of the strip, the other of the anvil plates being moved transversely towards the strip at the folding station, wherein the first and second carriage members have first and second link members respectively pivotally mounted thereto, the apparatus including a reciprocating bar upon which the first and second link members are mounted in mutually spaced relation, the angular orientation of one of the link members relative to the reciprocating bar being in one sense and the angular orientation of the other link member being in the opposite sense to said one sense whereby movement in one direction of the reciprocating bar will cause one of the anvil plates to move transversely away from the strip and the other of the anvil plates to move transversely towards the strip at the folding station wherein the guide means includes cam elements mounted upon the frame and co-operating cam members mounted upon the carriage members, said cam elements and members being operable at the end of a stroke of the reciprocating bar in one direction to cause one anvil plate to move in the direction of advance of the strip and simultaneously cause the other anvil plate to move in the reverse direction subsequent movement of the reciprocating bar (in the other direction) causing said other anvil plate to move transversely toward the strip at the folding station and at the end of the stroke of the reciprocating bar in the other direction the cam elements and members cause said other anvil plate to move in the direction of advance of the strip and said one anvil plate to move in the reverse direction.

8. Apparatus as claimed in claim 1 wherein the first anvil plate includes a first pair of forming shoulders and the first part of the folding mechanism includes a first pair of forming surfaces for respective co-operation with the forming shoulders to produce a step in the strip in the first direction, and wherein the second anvil plate includes a pair of forming shoulders and the second part of the folding mechanism includes a second pair of forming surfaces for respective co-operation with the second pair of forming surfaces to produce a step in the strip in the second direction.

9. Apparatus as claimed in claim 1 wherein the first and second anvil plates are mounted upon first and second carriage members, said carriage members carrying first and second support plates respectively, the first anvil and support plates being parallel and spaced apart a distance equal to one fold of the strip, the second anvil and support plates being parallel and spaced apart a distance equal to one fold of the strip, the first and second support plates acting respectively as a support for the folded strip when the first and second anvil plates are moved transversely into the folding station.

10. Apparatus as claimed in claim 1 wherein the first and second anvil plates have recesses therein extending in the transverse direction to allow the apparatus to operate on louvred strip.

11. Apparatus as claimed in claim 10 wherein the first and second parts of the folding mechanism are recessed to allow the apparatus to operate on louvred strip.

12. Apparatus as claimed in claim 11 wherein the first and second anvil plates are mounted upon first and second carriage members, said carriage members carrying first and second support plates respectively, the first anvil and support plates being parallel and spaced apart a distance equal to one fold of the strip, the second and support plates being parallel and spaced apart a distance equal to one fold of the strip, the first and second support plates acting respectively as a support for the folded strip when the first and second anvil plates are moved transversely into the folding station, and the first anvil and support plates are recessed on both sides thereof, and the second anvil and support plates are recessed on both sides thereof.

13. Apparatus as claimed in claim 12 wherein the first anvil plate includes a first pair of forming shoulders and the first part of the folding mechanism includes a first pair of forming surfaces for respective cooperation with the forming shoulders to produce a step in the strip in the first direction, and wherein the second anvil plate includes a pair of forming shoulders and the second part of the folding mechanism includes a second pair of forming surfaces for respective cooperation with the second pair of forming surfaces to produce a step in the strip in the second direction, and wherein the recess in the first part of the folding mechanism is between the first pair of forming surfaces and the recess in the second part of the folding mechanism is between the second pair of forming surfaces. 

1. Apparatus useful for the zig-zag folding of metal strip comprising: a frame carrying a folding mechanism at a folding station comprising first and second folding members: a first anvil plate and a second anvil plate each movable into and out of the folding station; means associated with each said anvil plate to move it, in a direction transverse to the plane of the strip, to a location adjacent to and extending transversely across the strip at the folding station, and to move the anvil in the direction of advance of the strip to feed the strip through the folding station; and synchronizing means to operate the first and second folding members in snychronism with the means for moving the anvil plates, said synchronizing means being operable to cause a cycle of operation in which: a. the first anvil station is moved in said transverse direction, into the folding station and the second anvil plate is moved in said transverse direction away from the strip to a position clear of the strip, b. the first folding member is operated to fold the strip about the first anvil plate, c. the first anvil plate is moved in said direction of advance of the strip and the second anvil plate is moved in the direction opposite to said advance direction, and d. the second anvil plate is moved in said transverse direction into the folding station and the first anvil plate is moved in said transverse direction away from the strip to a position clear of the strip.
 2. Apparatus as claimed in claim 1 wherein the first and second anvil plates are mounted upon first and second carriage members, and wherein the means to move the first anvil plate and the means to move the second anvil plate include guide means, said guide means being operable to move the first carriage member in the direction of advance of the strip while moving the second carriage member in the opposite direction.
 3. Apparatus as claimed in claim 2 wherein the first and second anvil plates are spaced and parallel and have adjacent ends, said guide means being operable to maintain said adjacent ends at a constant separation in said transverse direction.
 4. Apparatus as claimed in claim 3 wherein said separation is less than the transverse width of the strip.
 5. Apparatus as claimed in claim 3 wherein the guide means is operable to move the first and second anvil plates simultaneously in the transverse direction in the same sense, one of the anvil plates being moved transversely away from the strip so that the edge of said one anvil plate is clear of the side of the strip, the other of the anvil plates being moved transversely towards the strip at the folding station.
 6. Apparatus as claimed in claim 3 wherein the guide means is operable to move the first and second anvil plates simultaneously in the transverse direction in the same sense, one of the anvil plates being moved transversely away from the strip so that the edge of said one anvil plate is clear of the side of the strip, the other of the anvil plates being moved transversely towards the strip at the folding station, wherein the first and second carRiage members have first and second link members respectively pivotally mounted thereto, the apparatus including a reciprocating bar upon which the first and second link members are mounted in mutually spaced relation, the angular orientation of one of the link members relative to the reciprocating bar being in one sense and the angular orientation of the other link member being in the opposite sense to said one sense whereby movement in one direction of the reciprocating bar will cause one of the anvil plates to move transversely away from the strip and the other of the anvil plates to move transversely towards the strip at the folding station.
 7. Apparatus as claimed in claim 3 wherein the guide means is operable to move the first and second anvil plates simultaneously in the transverse direction of the same sense, one of the anvil plates being moved transversely away from the strip so that the edge of said one anvil plate is clear of the side of the strip, the other of the anvil plates being moved transversely towards the strip at the folding station, wherein the first and second carriage members have first and second link members respectively pivotally mounted thereto, the apparatus including a reciprocating bar upon which the first and second link members are mounted in mutually spaced relation, the angular orientation of one of the link members relative to the reciprocating bar being in one sense and the angular orientation of the other link member being in the opposite sense to said one sense whereby movement in one direction of the reciprocating bar will cause one of the anvil plates to move transversely away from the strip and the other of the anvil plates to move transversely towards the strip at the folding station wherein the guide means includes cam elements mounted upon the frame and co-operating cam members mounted upon the carriage members, said cam elements and members being operable at the end of a stroke of the reciprocating bar in one direction to cause one anvil plate to move in the direction of advance of the strip and simultaneously cause the other anvil plate to move in the reverse direction subsequent movement of the reciprocating bar (in the other direction) causing said other anvil plate to move transversely toward the strip at the folding station and at the end of the stroke of the reciprocating bar in the other direction the cam elements and members cause said other anvil plate to move in the direction of advance of the strip and said one anvil plate to move in the reverse direction.
 8. Apparatus as claimed in claim 1 wherein the first anvil plate includes a first pair of forming shoulders and the first part of the folding mechanism includes a first pair of forming surfaces for respective co-operation with the forming shoulders to produce a step in the strip in the first direction, and wherein the second anvil plate includes a pair of forming shoulders and the second part of the folding mechanism includes a second pair of forming surfaces for respective co-operation with the second pair of forming surfaces to produce a step in the strip in the second direction.
 9. Apparatus as claimed in claim 1 wherein the first and second anvil plates are mounted upon first and second carriage members, said carriage members carrying first and second support plates respectively, the first anvil and support plates being parallel and spaced apart a distance equal to one fold of the strip, the second anvil and support plates being parallel and spaced apart a distance equal to one fold of the strip, the first and second support plates acting respectively as a support for the folded strip when the first and second anvil plates are moved transversely into the folding station.
 10. Apparatus as claimed in claim 1 wherein the first and second anvil plates have recesses therein extending in the transverse direction to allow the apparatus to operate on louvred strip.
 11. Apparatus as claimed in claim 10 wherein the first and second parts of the folding mechaNism are recessed to allow the apparatus to operate on louvred strip.
 12. Apparatus as claimed in claim 11 wherein the first and second anvil plates are mounted upon first and second carriage members, said carriage members carrying first and second support plates respectively, the first anvil and support plates being parallel and spaced apart a distance equal to one fold of the strip, the second and support plates being parallel and spaced apart a distance equal to one fold of the strip, the first and second support plates acting respectively as a support for the folded strip when the first and second anvil plates are moved transversely into the folding station, and the first anvil and support plates are recessed on both sides thereof, and the second anvil and support plates are recessed on both sides thereof.
 13. Apparatus as claimed in claim 12 wherein the first anvil plate includes a first pair of forming shoulders and the first part of the folding mechanism includes a first pair of forming surfaces for respective co-operation with the forming shoulders to produce a step in the strip in the first direction, and wherein the second anvil plate includes a pair of forming shoulders and the second part of the folding mechanism includes a second pair of forming surfaces for respective co-operation with the second pair of forming surfaces to produce a step in the strip in the second direction, and wherein the recess in the first part of the folding mechanism is between the first pair of forming surfaces and the recess in the second part of the folding mechanism is between the second pair of forming surfaces. 